Lung Cancer is the leading cause of death among both men and women. Of the approximately 172,000 patients that are diagnosed every year with non small cell lung cancer (NSCLC) in the US, 55% present with advanced stage disease. The current treatment for advanced NSCLC is first line chemotherapy with a platinum-based doublet. Second line treatment for recurrent or progressive disease includes treatment with chemotherapy or treatment with an oral EGFR (epidermal growth factor receptor) tyrosine kinase inhibitor. Several mechanisms of resistance to EGFR tyrosine kinase inhibitors have been discovered. Presence of KRAS mutations is one of them. AZD6244 (ARRY-142886) is an investigational drug that is orally available and targets the critical kinase (MEK) in the mitogen-activated protein (MAP) kinase signal transduction pathway which is activated in NSCLC and is downstream of EGFR.